1. Hindawi Publishing Corporation
Journal of Obesity
Volume 2010, Article ID 231074, 7 pages
doi:10.1155/2010/231074
Clinical Study
Effects of Aquajogging in Obese Adults: A Pilot Study
Eveline J. M. Wouters,1, 2 Annemieke M. A. Van Nunen,3 Rinie Geenen,4
Ronette L. Kolotkin,5, 6 and Ad J. J. M. Vingerhoets2
1 Department of physiotherapy, Fontys University of Applied Sciences, P.O. Box 347, 5600 AH Eindhoven, The Netherlands
2 ClinicalPsychology Section, Tilburg University, P.O. box 90153, 5000 LE Tilburg, The Netherlands
3 PsyQ, Anderlechstraat 17, 5628 WB Eindhoven, The Netherlands
4 Department of Clinical and Health Psychology, Utrecht University, P.O. Box 80140, 3508 TC Utrecht, The Netherlands
5 Obesity and Quality of Life Consulting, 762 Ninth Street, Durham, NC 27705, USA
6 Department of Community and Family Medicine, Duke University School of Medicine, Durham, NC 27710, USA
Correspondence should be addressed to Eveline J. M. Wouters, e.wouters@fontys.nl
Received 27 May 2009; Revised 28 June 2009; Accepted 20 July 2009
Academic Editor: Jonatan R. Ruiz
Copyright © 2010 Eveline J. M. Wouters et al. This is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly
cited.
Aim and Method. To examine in obese people the potential effectiveness of a six-week, two times weekly aquajogging program on
body composition, fitness, health-related quality of life, and exercise beliefs. Fifteen otherwise healthy obese persons participated
in a pilot study. Results. Total fat mass and waist circumference decreased 1.4 kg (P = .03) and 3.1 cm (P = .005), respectively. The
distance in the Six-Minute Walk Test increased 41 meters (P = .001). Three scales of the Impact of Weight on Quality of Life-Lite
questionnaire improved: physical function (P = .008), self-esteem (P = .004), and public distress (P = .04). Increased perceived
exercise benefits (P = .02) and decreased embarrassment (P = .03) were observed. Conclusions. Aquajogging was associated with
reduced body fat and waist circumference and improved aerobic fitness and quality of life. These findings suggest the usefulness of
conducting a randomized controlled trial with long-term outcome assessments.
1. Introduction has been widely recommended to reduce the health risks
associated with overweight and obesity, even if the weight
Of the more than 1 billion overweight adults, at least 300 loss is minimal [19, 21, 22]. However, there is a substantial
million are obese (Body Mass Index [BMI] > 30 kg/m2 ) [1, elevated risk of injuries in obese persons, especially sprains
2]. Obesity increases the risk of chronic diseases, particularly and strains [23].
cardiovascular disease [3–5], type II diabetes mellitus [6, Physical exercise in water is a possibility to try to increase
7], and osteoarthritis [8, 9] in adults. Quality of life is physical and mental health of obese persons without the risk
severely reduced in obese persons [10, 11], and it is related of injuries. Aerobic activities in water have been found to be
to the degree of overweight [12]. Both obesity and living effective to improve aerobic fitness [24], and the effect on
a sedentary life have been associated independently with body composition has been demonstrated to be similar to
decreased quality of life [13] and stress regulation [14]. weight-bearing aerobic exercise on land [25]. Aquajogging
Physical exercise, combined with dietary adjustments, is a specific form of exercise which consists of simulated
massages, and baths, has been recommended for obesity running in deep water. In sports, aquajogging is used
since Hippocrates (fourth century BC) [15]. Aerobic exercise as low-impact training, for example, in the rehabilitation
produces less weight loss compared to caloric restriction phase after an injury. Aquajogging has been applied as a
programs [16]. Some recent studies, however, give evidence joint sparing intervention in rheumatologic diseases such as
for weight loss, especially abdominal weight loss, as a result osteoarthritis, in the pre- and postoperative management of
of exercise without caloric restriction [17–19]. Given the musculoskeletal diseases, and as an endurance and power
benefits for both physical and mental health [20], exercise training in cardiorespiratory disease [26–28]. According to

2. 2 Journal of Obesity
a search in the international reference system Web of Science, (Medisane). After the 6MWT the modified Borg scale was
aquajogging as an intervention to improve physical and applied to assess exertion. This measure consists of a visual
mental health in obese people has not been evaluated up till analog scale measurement ranging from 0 (no exertion) to
now. 10 (extreme exertion) [36–38].
The aim of this pilot study was to examine the safety
and potential effectiveness of a six-week aquajogging exercise 2.5. Health-Related Quality of Life. Health-related quality of
program on body composition, aerobic fitness, and health- life was measured using the Dutch version of the IWQOL-
related quality of life and exercise beliefs in obese people. Lite (short form of Impact of Weight on Quality of Life)
questionnaire. The IWQOL-Lite is a 31 item, obesity-specific
2. Materials and Methods health-related quality of life questionnaire. It consists of
five scales: physical function, self-esteem, sexual life, public
2.1. Participants. Participants were recruited with advertise- distress, and work [39]. The IWQOL-Lite has been shown
ments in a local paper, a poster in the waiting-room of local to have good internal consistency (Cronbach’s α range from
general practitioners, and an appeal on the website of the .90 to .96) [40], good test-retest reliability (correlations
Dutch Obesity Association. Inclusion criteria were a BMI of range from .83 to .94) [39], responsiveness to weight loss
at least 30 kg/m2 , age between 18 and 65 years, and the inten- and weight gain [41, 42], sensitivity to treatment seeking
tion to miss no more than two out of twelve training sessions. status [12] and degree of obesity [43], and a scale structure
Exclusion criteria were an identified somatic disease and use supported by confirmatory factor analysis [40].
of medications. The first 15 obese people who applied for
the intervention and fulfilled the inclusion and exclusion 2.6. Exercise Beliefs. Perceived barriers and benefits of physi-
criteria were invited to participate. The study was approved cal exercise were measured with the Physical Exercise Belief
by the institutional review board of Reinier van Arkel group Questionnaire (PEBQ) [44]. The PEBQ is partly derived
(mental health care department, ’s-Hertogenbosch) and all from the Dutch version of the Tampa scale of Kinesiophobia
participants provided written informed consent. [45] and consists of four scales. Two scales (fear of injury
and embarrassment) measure exercise barriers (high scores
2.2. Aquajogging Program. Participants enrolled in a stan- indicate high perceived barriers), and two scales (confidence
dard aquajogging program consisting of warming up, run- and exercise benefits) measure health benefits of exercise and
ning in deep water alternated with extra arm and leg exercise self confidence (high scores indicate high perceived
exercises, and cooling down, on stimulating music adapted benefits). The psychometric characteristics of the PEBQ have
to the phase of the program [29]. Twelve sessions were given, proved to be satisfactory in a sample of 278 obese and
two times per week during six weeks. Four physiotherapy severely obese patients [44].
graduate students alternatively carried out the program. Each Self-efficacy was assessed with The Dutch version of the
session lasted for one hour. Every participant could train 18-item Exercise Self-Efficacy Scale [46].
at his or her own level, although they were stimulated by
their trainer to gradually increase their effort throughout the 2.7. Physical Activity. Recent and current exercise behavior
session. was measured by asking “do you engage in sportive activ-
ities?” (response alternatives: yes or no), an open ended
2.3. Anthropometry and Body Composition. Height was question about the nature of these activities, and the time
measured using a tape measure fixed to the wall with spent on these activities weekly during the past year, using
participants on bare feet. Body weight, fat mass, and fat a 5-point scale response format ranging from “less than one
percentages were measured with the Tanita tbf-300 m [30, hour per week” to “more than four hours per week.” Walking
31]. The Tanita, a bioimpedance analysis method to measure and cycling activities during daily life, like shopping, going
body composition, has proven to be valid in obese people to work, or going to school, were rated on a five point scale,
[32], especially when monitoring modest changes in fat ranging from less than five minutes per day to more than 45
[33]. Waist circumference was measured with a special minutes per day.
waist circumference tape measure using the iliac crest as a
landmark. Measures were taken in duplicate and averaged. 2.8. Qualitative Evaluation. A brief individual open inter-
view with all participants after three and after six weeks of
2.4. Aerobic Fitness. The Six-Minute Walk Test (6MWT) was training evaluated the aquajogging program and its effects
performed outdoors in comfortable weather circumstances on daily activities as well as experienced negative effects
according to the procedure as described by the American during and after training, such as injuries or muscular pain.
Thoracic Society [34]. Participants were instructed to walk All interviews were performed at the same time for all
as much distance as possible without running in six minutes; participants, after three and six weeks of training.
encouragement was given as recommended [34]. The 6MWT
is a valid and reproducible tool to measure aerobic fitness in 2.9. Statistical Analysis. The mean changes between the
a group of obese people [35]. Heart rate values during rest baseline assessment scores and the scores after the aqua-
and immediately after the 6MWT were measured three times jogging program were compared for BMI, fat percentage,
and averaged, using the MD300-D finger pulse oximeter fat mass and waist circumference, the distance covered in

3. Journal of Obesity 3
Table 1: Anthropometric and demographic characteristics at poor quality of life at baseline (Table 3): the scores were on
baseline. average 10% to 20% lower than the scores in the general
Age, mean (range) years 44 (28–60) population [10]. The scores on three scales of the IWQOL-
Number of participants, male/female 2/13
Lite significantly improved after six weeks of aquajogging:
physical function increased from 62.8 (24.2) to 70.2 (21.7),
Body weight, mean (SD) kg 105.6 (13.2)
P < .01, self-esteem increased from 60.2 (26.5) to 70.2 (21.7),
Body Mass Index, mean (SD) kg/m2 37.9 (5.0) P < .01, and public distress increased from 78.2 (17.8) to 83.0
Educational level, n (%) (14.3), P < .05.
<9 years of education 3 (20)
9–12 years of education, no high school degree 2 (13)
3.5. Changes in Exercise Beliefs. The PEBQ showed a sig-
High school graduates 5 (33) nificant (P < .05) increase in perceived exercise benefits
Bachelor or Master degree 5 (33) after six weeks of aquajogging (Table 3). Eight out of 14
participants indicated increased perceived exercise benefits,
one participant perceived decreased exercise benefits, and
the 6MWT, and the heart rate during rest and immediately five showed no changes. Ten of 14 participants indicated
after the 6MWT, the Borg exertion rating, the scale scores decreased and three increased embarrassment, the mean
on the IWQOL-Lite, the PEBQ, and the Exercise Self-Efficacy change being statistically significant (P < .05). Fear of
Scale. Considering the small sample size, the nonparametric injury, confidence, and exercise self-efficacy did not show any
Wilcoxon-signed ranks test was used to examine the signif- significant change after 6 weeks of aquajogging (Table 3).
icance of the differences between baseline and at six weeks.
All analyses were conducted using the program Statistical
Package for the Social Sciences (SPSS Version 14.0; SPSS Inc., 3.6. Qualitative Evaluation. Thirteen participants were very
Chicago, IL, USA). Results are presented as mean (SD). positive about aquajogging as a way of physical exer-
cise. All participants perceived improved aerobic fitness
in daily life and reported improved self confidence. Most
3. Results participants reported decreased clothing size. Participants
experienced decreased appetite, and three spontaneously
3.1. Descriptives. Fifteen otherwise healthy obese persons
made an appointment with a dietician to start dietary
entered the program. Anthropometric and demographic
treatment after the end of the aquajogging program. Injuries
characteristics at baseline are presented in Table 1. One
or uncomfortable muscular pain were not experienced by
(male) participant dropped out of the study a week before
any participant during or after the training. All participants
the end of the program because of a respiratory infection.
valued the fact that they exercised in a group with the same
Thirteen of the participants were women with a mean age
obese condition.
of 44 years and a mean BMI of 38 kg/m2 . One woman used
antidepressive medication (Duloxetine), a serotonin and
noradrenalin reuptake inhibitor not influencing body weight 4. Discussion
[47], 60 mg daily. The mean participants’ self-reported daily
physical activity, including sportive activities, was less than After a 6-week aquajogging group program without dietary
30 minutes. No diets with the intention of extra weight loss restriction in obese people, improvements in body composi-
were used during the program. tion, aerobic fitness, and quality of life were observed.
With respect to weight loss, our study is in agreement
with previous findings that weight loss is limited after
3.2. Changes in Body Composition. Weight, BMI, and fat
physical activity as monotherapy [16]. Some studies suggest
percentage were lower after six weeks compared to baseline,
that physical exercise may result in—at best—modest weight
but the differences were not statistically significant (Table 2).
loss independent of the effect of caloric reduction through
Fat mass decreased in 11 and increased in 3 participants. The
diet [17–19]. These studies employed strenuous physical
change of fat mass from 48.5 (10.5) to 47.1 (10.8) kg was
exercise regimes equal to a daily energy expenditure of
significant (P < .05). Waist circumference decreased in 12
500 kcal (women) or 700 kcal (men). Although we did not
and increased in two participants (a statistically significant
measure this variable, the reduction in energy expenditure
change, P < .01).
is supposed to be low in our intervention, because the
program lasted for one hour regardless of caloric loss and was
3.3. Changes in Aerobic Fitness. The distance walked in performed only twice a week. If the training program had
the 6MWT was significantly longer after six weeks of covered a longer period of time, with higher frequency and
aquajogging; it changed from 574 (42) to 615 (37) meters intensity, better results on weight would have been expected.
(P < .01) (Table 2); all participants showed an increase in On the other hand, although the relatively low intensity
walking distance. Both heart rate and perceived exertion after of aquajogging may make it less effective to lose weight,
the 6MWT did not alter after 6 weeks of aquajogging. it is considered a suitable intervention for obese people,
because they perceive it as a positive exercise experience,
3.4. Changes in Health-Related Quality of Life. The scores on which has been reported as being important in previous
all scales of the IWQOL-Lite in the study group reflected a studies focused on physical exercise with obese patients [48].

4. 4 Journal of Obesity
Table 2: Effects of aquajogging on body composition and aerobic fitness of 14 participants, means (SD). BMI: Body Mass Index; HR: heart
rate; 6MWT: 6 minute walk test.
Baseline Six weeks P values1
Body composition
Weight (kg) 106.1 (13.7) 104.7 (14.1) .06
BMI (kg/m2 ) 38.2 (5.0) 37.7 (5.1) .06
Fat percentage (%) 45.5 (5.9) 44.7 (6.1) .06
Fat mass (kg) 48.5 (10.5) 47.1 (10.8) .03
Waist circumference (cm) 113.5 (10.4) 110.4 (10.4) .005
Aerobic fitness
HR rest (bpm) 85 (14) 82 (13) .60
HR after 6MWT (bpm) 131 (19) 135 (21) .18
Distance 6MWT (m) 574 (42) 615 (37) .001
Borg exertion score 5.3 (1.6) 6.2 (1.8) .11
1
Wilcoxon signed ranks test.
Table 3: Health-related quality of life and exercise beliefs of 14 participants: means (SD).
Baseline Six weeks P values1
IWQOL-Lite 2
Physical function 62.8 (24.2) 69.8 (18.5) .008
Self-esteem 60.2 (26.5) 70.2 (21.7) .004
Sexual life 84.8 (20.8) 88.8 (13.5) .26
Public distress 78.2 (17.8) 83.0 (14.3) .04
Work 90.2 (10.0) 91.3 (9.0) .60
PEBQ3
Fear of injury 9.9 (4.0) 9.6 (3.2) .75
Embarrassment 12.6 (4.3) 10.4 (4.5) .03
Confidence 8.7 (2.6) 9.1 (3.0) .48
Exercise benefits 17.4 (1.8) 18.3 (2.0) .02
Exercise Self-Efficacy 67.3 (16.6) 70.4 (16.8) .28
1
Wilcoxon signed ranks test.
2 IWQOL-Lite: Impact of weight on quality of life—short form.
3 PEBQ: Physical Exercise Belief Questionnaire.
Physical activity has been recommended for obese persons that reported in healthy adults [57]. The mean increase in
because it increases cardiorespiratory fitness independent of walking distance of 41 meters is in between the effect of
caloric loss [49, 50]. Obese persons are more likely to have corticosteroid inhalation, and exercise and diaphragmatic
hypertension, dyslipidemia, and the metabolic syndrome strength training, in COPD patients [34]. This possibly
[51, 52]. Exercise training has been found to decrease heart clinically relevant change in distance should be interpreted
rate at rest [53], but a substantial effect of aquajogging with some caution. Perhaps the results are partly due to the
on resting heart rate was not found in our study, perhaps learning effect of doing the test for the second time [35]. Our
because the duration, frequency, or intensity of the training study did not find positive effects of aquajogging on exertion
was too low [54]. Obesity-related comorbid conditions scores after the walking test. However, because baseline
(especially insulin resistance) have been found to be reduced exertion and postintervention exertion scores related to a
by increased daily physical activity without caloric restriction different physical performance after the walking test on the
[18]. Our study observed a significant reduction of fat mass two occasions, our study does not allow a final evaluation
and waist circumference, a visceral fat measure that is a risk of effects of aquajogging on physical exertion. Perhaps
indicator for comorbidity [55, 56]. The results of our pilot increased confidence made the participants to exceed their
intervention in obese people suggest that promising health limits in the walking test after the intervention.
effects can be expected from aquajogging, even when weight After the aquajogging program, the health-related quality
loss is minimal. of life scores of our participants showed an improvement
We used the Six-Minute Walk test as a measure of in public distress and in the scales that normally deviate
functional capacity [34]. The mean baseline walking distance most from normal weight people: physical function and
observed in our obese participants was slightly lower than self-esteem [10, 12]. In addition, exercise embarrassment

5. Journal of Obesity 5
decreased, and the perception of exercise benefits increased References
after the aquajogging program, as indicated by the PEBQ
findings and the open interviews. Our pilot study shows that [1] WHO, “Global strategy on diet, physical activity and health,”
2009.
quality of life improves and suggests that aquajogging might
[2] B. M. Popkin, “Global nutrition dynamics: the world is
bring about these effects.
shifting rapidly toward a diet linked with noncommunicable
Aquatic exercise has been proved beneficial in other diseases,” American Journal of Clinical Nutrition, vol. 84, no. 2,
patients with conditions who are at risk when performing pp. 289–298, 2006.
strenuous exercise like osteoarthritis [27, 58, 59], fibromyal- [3] F. Abbasi, B. W. Brown Jr., C. Lamendola, T. McLaughlin,
gia [60], and sports injuries [28]. The severely obese people and G. M. Reaven, “Relationship between obesity, insulin
also belong to this group for whom aquatic exercise may be resistance, and coronary heart disease risk,” Journal of the
the physical exercise intervention of choice, because they are American College of Cardiology, vol. 40, no. 5, pp. 937–943,
unable to perform large amounts of exercise over the short 2002.
term [61], and there is a substantial risk of injury [23]. In [4] C. Curioni, C. Andr´ , and R. Veras, “Weight reduction for
e
our study, no participants experienced any injury suggesting primary prevention of stroke in adults with overweight or
that aquajogging might be a safe way of exercising in obesity. obesity,” Cochrane Database of Systematic Reviews, no. 4,
Article ID CD006062, 2006.
There are limitations to the present study, including the
[5] J. R. Ghosh and A. R. Bandyopadhyay, “Comparative evalu-
small sample size, the predominance of women, the lack
ation of obesity measures: relationship with blood pressures
of a randomized, untreated control group, the relatively and hypertension,” Singapore Medical Journal, vol. 48, no. 3,
short duration of the intervention, and the absence of pp. 232–235, 2007.
a follow up evaluation to examine persistence of effects. [6] C. Daousi, I. F. Casson, G. V. Gill, I. A. MacFarlane, J. P. H.
Future evaluations of aquajogging programs should include Wilding, and J. H. Pinkney, “Prevalence of obesity in type
muscular fitness, because higher resistance against the limbs’ 2 diabetes in secondary care: association with cardiovascular
movement created by the water could improve both car- risk factors,” Postgraduate Medical Journal, vol. 82, no. 966, pp.
diorespiratory and muscular fitness. This was not tested in 280–284, 2006.
our study. Because it was considered of utmost importance [7] M. Serrano Rios, “Relationship between obesity and the
that participants learned to like physical exercise, we did increased risk of major complications in non-insulin-
not stimulate high-intensity exercise and did not repeatedly dependent diabetes mellitus,” European Journal of Clinical
Investigation, vol. 28, supplement 2, pp. 14–18, 1998.
assess variables such as heart rate, Borg’s perceived exertion
[8] C. B. Eaton, “Obesity as a risk factor for osteoarthritis:
scale, or training diaries. Our study did also not take
mechanical versus metabolic,” Medicine and Health, vol. 87,
into account possible concomitant dietary changes. As in no. 7, pp. 201–204, 2004.
many other studies, our study population consisted of [9] A. Powell, A. J. Teichtahl, A. E. Wluka, and F. M. Cicuttini,
participants who volunteered for the program. This restricts “Obesity: a preventable risk factor for large joint osteoarthritis
the generalizability of the results to obese people who which may act through biomechanical factors,” British Journal
may be considered motivated to participate in this kind of of Sports Medicine, vol. 39, no. 1, pp. 4–5, 2005.
intervention. [10] A. M. A. Van Nunen, E. J. M. Wouters, A. J. J. M. Vingerhoets,
J. J. Hox, and R. Geenen, “The health-related quality of life of
obese persons seeking or not seeking surgical or non-surgical
5. Conclusions treatment: a meta-analysis,” Obesity Surgery, vol. 17, no. 10,
pp. 1357–1366, 2007.
Physical exercise in water is a possibility to try to increase [11] R. L. Kolotkin, K. Meter, and G. R. Williams, “Quality of life
physical and mental health of obese persons without the and obesity,” Obesity Reviews, vol. 2, no. 4, pp. 219–229, 2001.
risk of injuries. In a six-week open-trial in obese persons, [12] R. L. Kolotkin, R. D. Crosby, and G. R. Williams, “Health-
aquajogging without caloric restrictions was associated with related quality of life varies among obese subgroups,” Obesity
reductions in body fat and waist circumference and with Research, vol. 10, no. 8, pp. 748–756, 2002.
improvement of aerobic fitness and quality of life. These [13] G. T. C. Ko, “Both obesity and lack of physical activity are
findings suggest the usefulness of conducting a randomized associated with a less favorable health-related quality of life in
Hong Kong Chinese,” American Journal of Health Promotion,
controlled trial with long-term outcome assessments. The
vol. 21, no. 1, pp. 49–52, 2006.
indication that aquajogging results in physical and mental [14] A. Tsatsoulis and S. Fountoulakis, “The protective role of
health benefits for obese people suggests that it might be exercise on stress system dysregulation and comorbidities,”
a valuable therapy in itself or as an adjunct to a dietary Annals of the New York Academy of Sciences, vol. 1083, pp. 196–
intervention. 213, 2006.
[15] G. A. Bray, “Obesity: historical development of scientific and
cultural ideas,” International Journal of Obesity, vol. 14, no. 11,
Acknowledgments pp. 909–926, 1990.
[16] W. C. Miller, D. M. Koceja, and E. J. Hamilton, “A meta-
The authors wish to thank Thijs van Bree, Stefan Janssen, analysis of the past 25 years of weight loss research using
Serv´ van Veggel, and Rob Westerlaken for their excellent
e diet, exercise or diet plus exercise intervention,” International
supervising, testing, and training the participants of this Journal of Obesity, vol. 21, no. 10, pp. 941–947, 1997.
study, and the staff of Thermae Son, who kindly provided [17] R. Ross, D. Dagnone, P. J. H. Jones, et al., “Reduction in obesity
all swimming facilities. and related comorbid conditions after diet-induced weight

6. 6 Journal of Obesity
loss or exercise-induced weight loss in men: a randomized, energy expenditure,” Obesity, vol. 16, no. 8, pp. 1953–1956,
controlled trial,” Annals of Internal Medicine, vol. 133, no. 2, 2008.
pp. 92–103, 2000. [33] M. Neovius, J. Udd´ n, and E. Hemmingsson, “Assessment of
e
[18] R. Ross, J. A. Freeman, and I. Janssen, “Exercise alone change in body fat percentage with DXA and eight-electrode
is an effective strategy for reducing obesity and related BIA in centrally obese women,” Medicine and Science in Sports
comorbidities,” Exercise and Sport Sciences Reviews, vol. 28, no. and Exercise, vol. 39, no. 12, pp. 2199–2203, 2007.
4, pp. 165–170, 2000. [34] R. O. Crapo, R. Casaburi, A. L. Coates, et al., “ATS statement:
[19] R. Ross, I. Janssen, J. Dawson, et al., “Exercise-induced guidelines for the six-minute walk test,” American Journal of
reduction in obesity and insulin resistance in women: a Respiratory and Critical Care Medicine, vol. 166, no. 1, pp. 111–
randomized controlled trial,” Obesity Research, vol. 12, no. 5, 117, 2002.
pp. 789–798, 2004. [35] U. E. Larsson and S. Reynisdottir, “The six-minute walk test
[20] F. J. Penedo and J. R. Dahn, “Exercise and well-being: a review in outpatients with obesity: reproducibility and known group
of mental and physical health benefits associated with physical validity,” Physiotherapy Research International, vol. 13, no. 2,
activity,” Current Opinion in Psychiatry, vol. 18, no. 2, pp. 189– pp. 84–93, 2008.
193, 2005. [36] R. C. Wilson and P. W. Jones, “Long-term reproducibility of
[21] D. L. Heim, C. A. Holcomb, and T. M. Loughin, “Exercise mit- Borg scale estimates of breathlessness during exercise,” Clinical
igates the association of abdominal obesity with high-density Science, vol. 80, no. 4, pp. 309–312, 1991.
lipoprotein cholesterol in premenopausal women: results from [37] K. R. Kendrick, S. C. Baxi, and R. M. Smith, “Usefulness of the
the third National Health and Nutrition Examination Survey,” modified 0-10 Borg scale in assessing the degree of dyspnea
Journal of the American Dietetic Association, vol. 100, no. 11, in patients with COPD and asthma,” Journal of Emergency
pp. 1347–1353, 2000. Nursing, vol. 26, no. 3, pp. 216–222, 2000.
[22] K. Shaw, H. Gennat, P. O’Rourke, and C. Del Mar, “Exercise [38] G. Borg, “Perceived exertion as an indicator of somatic stress,”
for overweight or obesity,” Cochrane Database of Systematic Scandinavian Journal of Rehabilitation Medicine, vol. 2, no. 2,
Reviews, no. 4, Article ID CD003817, 2006. pp. 92–98, 1970.
[23] E. A. Finkelstein, H. Chen, M. Prabhu, J. G. Trogdon, and P. S. [39] R. L. Kolotkin and R. D. Crosby, “Psychometric evaluation
Corso, “The relationship between obesity and injuries among of the impact of weight on quality of life-lite questionnaire
U.S. adults,” American Journal of Health Promotion, vol. 21, no. (IWQOL-Lite) in a community sample,” Quality of Life
5, pp. 460–468, 2007. Research, vol. 11, no. 2, pp. 157–171, 2002.
[40] R. L. Kolotkin, R. D. Crosby, K. D. Kosloski, and G. R.
[24] T. P. Reilly, C. N. Dowzer, and N. T. Cable, “The physiology of
Williams, “Development of a brief measure to assess quality
deep-water running,” Journal of Sports Sciences, vol. 21, no. 12,
of life in obesity,” Obesity Research, vol. 9, no. 2, pp. 102–111,
pp. 959–972, 2003.
2001.
[25] E. Gappmaier, W. Lake, A. G. Nelson, and A. G. Fisher,
[41] S. G. Engel, R. D. Crosby, R. L. Kolotkin, et al., “Impact of
“Aerobic exercise in water versus walking on land: effects on
weight loss and regain on quality of life: mirror image or
indices of fat reduction and weight loss of obese women,”
differential effect?” Obesity Research, vol. 11, no. 10, pp. 1207–
Journal of Sports Medicine and Physical Fitness, vol. 46, no. 4,
1213, 2003.
pp. 564–569, 2006.
[42] R. L. Kolotkin, R. D. Crosby, G. R. Williams, G. G. Hartley,
[26] A. Cider, M. Schaufelberger, K. S. Sunnerhagen, and B. Ander-
and S. Nicol, “The relationship between health-related quality
sson, “Hydrotherapy—a new approach to improve function in
of life and weight loss,” Obesity Research, vol. 9, no. 9, pp. 564–
the older patient with chronic heart failure,” European Journal
571, 2001.
of Heart Failure, vol. 5, no. 4, pp. 527–535, 2003.
[43] M. A. White, P. M. O’Neil, R. L. Kolotkin, and T. K. Byrne,
[27] A. Foley, J. Halbert, T. Hewitt, and M. Crotty, “Does “Gender, race, and obesity-related quality of life at extreme
hydrotherapy improve strength and physical function in levels of obesity,” Obesity Research, vol. 12, no. 6, pp. 949–955,
patients with osteoarthritis—a randomised controlled trial 2004.
comparing a gym based and a hydrotherapy based strength- [44] J. K. Larsen, R. Geenen, B. van Ramshorst, et al., “Binge
ening programme,” Annals of the Rheumatic Diseases, vol. 62, eating and exercise behavior after surgery for severe obesity:
no. 12, pp. 1162–1167, 2003. a structural equation model,” International Journal of Eating
[28] R. Zenhausern and W. O. Frey, “Aquajogging in the rehabilita- Disorders, vol. 39, no. 5, pp. 369–375, 2006.
tion process,” Orthopade, vol. 26, pp. 926–929, 1997. [45] J. Roelofs, L. Goubert, M. L. Peters, J. W. S. Vlaeyen, and
[29] A. Van der Sluis, “Aquajogging, fitness programma met de G. Crombez, “The Tampa Scale for Kinesiophobia: further
wet belt [aquajogging, fitness program with a flotation belt],” examination of psychometric properties in patients with
Doorn, N.R.Z., 1993. chronic low back pain and fibromyalgia,” European Journal of
[30] S. A. Jebb, T. J. Cole, D. Doman, P. R. Murgatroyd, and A. Pain, vol. 8, no. 5, pp. 495–502, 2004.
M. Prentice, “Evaluation of the novel Tanita body-fat analyser [46] A. Bandura, Self-Efficacy: The Exercise of Control, W.H.
to measure body composition by comparison with a four- Freeman, New York, NY, USA, 1997.
compartment model,” British Journal of Nutrition, vol. 83, no. [47] CVZ, Farmacotherapeutisch Kompas, Bohn Stafleu van
2, pp. 115–122, 2000. Loghum, Houten, The Netherlands, 2007.
[31] J. D. Ritchie, C. K. Miller, and H. Smiciklas-Wright, “Tanita [48] S. Schelling, S. Munsch, A. H. Meyer, P. Newark, E. Biedert,
foot-to-foot bioelectrical impedance analysis system validated and J. Margraf, “Increasing the motivation for physical activity
in older adults,” Journal of the American Dietetic Association, in obese patients,” International Journal of Eating Disorders,
vol. 105, no. 10, pp. 1617–1619, 2005. vol. 42, no. 2, pp. 130–138, 2009.
[32] G. W. Strain, J. Wang, M. Gagner, A. Pomp, W. B. Inabnet, [49] T. S. Church, C. P. Earnest, J. S. Skinner, and S. N.
and S. B. Heymsfield, “Bioimpedance for severe obesity: Blair, “Effects of different doses of physical activity oncar-
comparing research methods for total body water and resting diorespiratory fitness among sedentary, overweight or obese

7. Journal of Obesity 7
postmenopausal women with elevated blood pressure: a
randomized controlled trial,” Journal of the American Medical
Association, vol. 297, no. 19, pp. 2081–2091, 2007.
[50] A. Quinn, C. Doody, and D. O’Shea, “The effect of a physical
activity education programme on physical activity, fitness,
quality of life and attitudes to exercise in obese females,”
Journal of Science and Medicine in Sport, vol. 11, no. 5, pp. 469–
472, 2008.
[51] “Clinical guidelines on the identification, evaluation, and
treatment of overweight and obesity in adults—the evidence
report. National Institutes of Health,” Obesity Research, vol. 6,
supplement 2, pp. 51S–209S, 1998.
[52] I. Janssen, P. T. Katzmarzyk, R. Ross, et al., “Fitness alters the
associations of BMI and waist circumference with total and
abdominal fat,” Obesity Research, vol. 12, no. 3, pp. 525–537,
2004.
[53] W. C. Levy, M. D. Cerqueira, G. D. Harp, et al., “Effect of
endurance exercise training on heart rate variability at rest in
healthy young and older men,” American Journal of Cardiology,
vol. 82, no. 10, pp. 1236–1241, 1998.
[54] E. J. C. De Geus, L. J. P. van Doornen, D. C. de Visser, and
J. F. Orlebeke, “Existing and training induced differences in
aerobic fitness: their relationship to physiological response
patterns during different types of stress,” Psychophysiology, vol.
27, no. 4, pp. 457–478, 1990.
[55] P. T. Katzmarzyk, I. Janssen, R. Ross, T. S. Church, and
S. N. Blair, “The importance of waist circumference in the
definition of metabolic syndrome: prospective analyses of
mortality in men,” Diabetes Care, vol. 29, no. 2, pp. 404–409,
2006.
[56] S. Klein, D. B. Allison, S. B. Heymsfield, et al., “Waist
circumference and cardiometabolic risk: a consensus state-
ment from Shaping America’s Health: association for Weight
Management and Obesity Prevention; NAASO, the Obesity
Society; the American Society for Nutrition; and the American
Diabetes Association,” Diabetes Care, vol. 30, no. 6, pp. 1647–
1652, 2007.
[57] W. J. Gibbons, N. Fruchter, S. Sloan, and R. D. Levy, “Reference
values for a multiple repetition 6-minute walk test in healthy
adults older than 20 years,” Journal of Cardiopulmonary
Rehabilitation, vol. 21, no. 2, pp. 87–93, 2001.
[58] F. B. Wyatt, S. Milam, R. C. Manske, and R. Deere, “The
effects of aquatic and traditional exercise programs on persons
with knee osteoarthritis,” Journal of Strength and Conditioning
Research, vol. 15, no. 3, pp. 337–340, 2001.
[59] T.-J. Wang, B. Belza, F. Elaine Thompson, J. D. Whitney, and K.
Bennett, “Effects of aquatic exercise on flexibility, strength and
aerobic fitness in adults with osteoarthritis of the hip or knee,”
Journal of Advanced Nursing, vol. 57, no. 2, pp. 141–152, 2007.
[60] M. R. Assis, L. E. Silva, A. M. Alves, et al., “A randomized
controlled trial of deep water running: clinical effectiveness of
aquatic exercise to treat fibromyalgia,” Arthritis Rheumatism,
vol. 55, no. 1, pp. 57–65, 2006.
[61] T. A. Wadden and A. J. Stunkard, Handbook of Obesity
Treatment, The Guilford Press, New York, NY, USA, 2004.